This is a tutorial explaining how to get the "Fuel Efficient" achievement.
Follow the steps below:

1) Start a game on the zombie map "Tranzit".
2) Look around the main room and find the three parts of the turbine.
3) Put the turbine together.
4) Pick up the turbine.
5) Open the door to outside.
6) Look to your left and you will notice a lantern.
7) Place the turbine underneath the lantern.
8) Watch as it begins to glow green.
9) Walk into the fog that appears.
10) A denizen of the wood will jump and grab onto you.
11) Run to the lantern and the goblin will jump off of you and turn into a portal.
12) Stand on top of the portal and jump.
13) You will be teleported to a random place.
14) The achievement will now pop up.

Here is a video tutorial: